As many as 20 percent of people may have a benign cyst or tumor in their pituitary gland. The vast majority of pituitary tumors are noncancerous, but can cause headaches and profound fatigue, and can also disrupt hormone ...

Every addiction is characterized by a strong desire for a certain addictive substance, be it nicotine, alcohol or other drug. Researchers at the University of Basel in Switzerland recently conducted a study on heroin addiction ...

(HealthDay)—Biomarkers can be used to guide decisions on systemic therapy for women with metastatic breast cancer, according to the American Society of Clinical Oncology Clinical Practice Guideline published online July ...

In animal models, acupuncture appears to impact the same biologic pathways ramped up by pain and stress, analogous to what drugs do in humans. Georgetown University Medical Center (GUMC) researchers say their animal study, ...

Johanna Olson, MD, and her colleagues at Children's Hospital Los Angeles, provide care for the largest number of transyouth in the U.S. and have enrolled 101 patients in a study to determine the safety and efficacy of treatment ...

Nearly a third of breast cancer survivors in Appalachia are not taking the critical, potentially life-saving follow-up treatment - despite having insurance that would pay for it, a troubling new study has found.

A study of long-term thyroid cancer outcomes shows, among other findings, that moderate suppression of thyroid-stimulating hormone (TSH), which drives the disease, may be as beneficial as more extreme hormone suppression. ...

A new study from Lund University in Sweden shows that women with low levels of an anti-stress hormone have an increased risk of getting breast cancer. The study is the first of its kind on humans and confirms previous similar ...

Jul 14, 2015

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Hormone

Hormones (from Greek ὁρμή - "impetus") are chemicals released by cells that affect cells in other parts of the body. Only a small amount of hormone is required to alter cell metabolism. It is essentially a chemical messenger that transports a signal from one cell to another. All multicellular organisms produce hormones; plant hormones are also called phytohormones. Hormones in animals are often transported in the blood. Cells respond to a hormone when they express a specific receptor for that hormone. The hormone binds to the receptor protein, resulting in the activation of a signal transduction mechanism that ultimately leads to cell type-specific responses.

Endocrine hormone molecules are secreted (released) directly into the bloodstream, while exocrine hormones (or ectohormones) are secreted directly into a duct, and from the duct they either flow into the bloodstream or they flow from cell to cell by diffusion in a process known as paracrine signalling.